#!/usr/bin/env ruby

def stop_grader(id)
  if id==:all
    File.open(File.dirname(__FILE__) + "/stop.all",'w').close
  else
    File.open(File.dirname(__FILE__) + "/stop.#{id}",'w').close
  end
end

def check_stopfile
  FileTest.exist?(File.dirname(__FILE__) + "/stop.all") or
    FileTest.exist?(File.dirname(__FILE__) + "/stop.#{Process.pid}")
end

def clear_stopfile
  if FileTest.exist?(File.dirname(__FILE__) + "/stop.#{Process.pid}")
    File.delete(File.dirname(__FILE__) + "/stop.#{Process.pid}")
  end
end

def config
  Grader::Configuration.get_instance
end

def log_file_name
  if !File.exists?(config.log_dir)
    raise "Log directory does not exist: #{config.log_dir}"
  end
  config.log_dir + 
    "/#{GRADER_ENV}_#{config.grader_mode}.#{Process.pid}"
end

def log(str)
  if config.talkative
    puts str
  end
  if config.logging
    fp = File.open(log_file_name,"a")
    fp.puts("GRADER: #{Time.new.strftime("%H:%M")} #{str}")
    fp.close
  end
end

def display_manual
  puts <<USAGE
Grader.
using: (1) grader 
       (2) grader environment [mode] [options]
       (3) grader stop [all|pids-list]
       (4) grader --help
(1) call grader with environment = 'exam', mode = 'queue'
(2) possible modes are: 'queue', 'test_request', 'prob', 'sub', 'contest', and 'autonew'
  queue: repeatedly check the task queue and grade any available tasks

  prob:  re-grade every user latest submission of the specific problem.
         the problem name must be specified by the next argument.

         additional options:
            --all-sub      re-grade every submissions instead of just the latest submission of each user.
	    --only-error   re-grade only submissions that are "error during grading"

  sub:   re-grader the specified submission.
         The submission ID to be re-graded must be specified by the next argument.

  options:
    --err-log   log error to a file in the log dir

(3) create stop-file to stop running grader in queue mode
(4) You are here.
USAGE
end

def process_options_and_stop_file
  # The list of options are:
  #   - stop [all|process ids]
  #   -  
  
  # Process 'help' option
  if (ARGV.length==1) and (/help/.match(ARGV[0]))
    display_manual
    exit(0)
  end

  # Process 'stop' option.
  if (ARGV.length >= 1) and (ARGV[0]=='stop')
    if ARGV.length==1
      puts "you should specify pid-list or 'all'"
      display_manual
    elsif (ARGV.length==2) and (ARGV[1]=='all')
      stop_grader(:all)
      puts "A global stop file ('stop.all') created."
      puts "You should remove it manually later."
    else
      (1..ARGV.length-1).each do |i|
        stop_grader(ARGV[i])
      end
      puts "stop file(s) created"
    end
    exit(0)
  end

  # Check stop file.
  if check_stopfile
    puts "Stop file exists.  Terminated."
    clear_stopfile
    exit(0)
  end

  #default options
  options = {
    :mode => 'queue',
    :environment => 'exam',
    :dry_run => false,
  }

  # Process mode and environment option
  if ARGV.length >= 1
    options[:environment] = ARGV.shift
    if ARGV.length >=1
      options[:mode] = ARGV.shift
    end
  else
    puts 'no argument specified, using default mode and environment.'
  end

  options[:dry_run] = (ARGV.delete('--dry') != nil)
  if options[:dry_run] and (not ['prob','contest','autonew'].include? options[:mode])
    puts "Dry run currently works only for 'prob' or 'contest' modes."
    exit(0)
  end

  options[:report] = (ARGV.delete('--report') != nil)
  if options[:report] and (not ['prob','contest','autonew'].include? options[:mode])
    puts "Report currently works only for 'prob' or 'contest' modes."
    exit(0)
  end

  options[:all_sub] = (ARGV.delete('--all-sub') != nil)
  options[:only_err] = (ARGV.delete('--only-error') != nil)

  options[:err_log] = (ARGV.delete('--err-log') != nil)

  return options
end

class ResultCollector
  def initialize
    @results = {}
    @problems = {}
    @users = {}
  end

  def after_save_hook(submission, grading_result)
  end

  def save(submission, grading_result)
    user = submission.user
    problem = submission.problem
    if not @problems.has_key? problem.id
      @problems[problem.id] = problem
    end
    if not @users.has_key? user.id
      @users[user.id] = user
    end
    @results[[user.id, problem.id]] = grading_result

    after_save_hook(submission, grading_result)
  end

  def print_report_by_user
    puts "---------------------"
    puts "       REPORT"
    puts "---------------------"

    print "login,email"
    @problems.each_value do |problem|
      print ",#{problem.name}"
    end
    print "\n"

    @users.each_value do |user|
      print "#{user.login},#{user.email}"
      @problems.each_value do |problem|
        if @results.has_key? [user.id, problem.id]
          print ",#{@results[[user.id,problem.id]][:points]}"
        else
          print ","
        end
      end
      print "\n"
    end
  end
end

def grader_general_loop(engine, grader_proc, options)
  runner = Grader::Runner.new(engine, grader_proc)
  while true
    
    if check_stopfile    # created by calling grader stop
      clear_stopfile
      log "stopped (with stop file)"
      break
    end

    task = yield(runner)

    if task==nil
      sleep(1)
    end
  end
end

def grader_queue_loop(grader_proc, options)
  log "Grader: queue"
  engine = Grader::Engine.new
  grader_general_loop(engine, grader_proc, options) do |runner| 
    runner.grade_oldest_task
  end
end

def grader_test_request_loop(grader_proc, options)
  log "Grader: test_request"
  engine = Grader::Engine.new(:room_maker => Grader::TestRequestRoomMaker.new,
                              :reporter => Grader::TestRequestReporter.new)
  grader_general_loop(engine, grader_proc, options) do |runner| 
    runner.grade_oldest_test_request
  end
end

def grader_autonew_loop(grader_proc, options)
  log "Grader: autonew"

  if options[:report]
    result_collector = ResultCollector.new
  else
    result_collector = nil
  end

  if options[:dry_run]
    puts "Running in dry mode"
  end

  prob_reporter = Grader::SubmissionReporter.new(:dry_run => options[:dry_run],
                                                 :result_collector => result_collector)

  engine = Grader::Engine.new(:reporter => prob_reporter)
  runner = Grader::Runner.new(engine, grader_proc)
  
  grader_proc.report_active if grader_proc!=nil

  latest_submitted_at = nil
  graded_submission_ids = {}

  while true
    
    if check_stopfile    # created by calling grader stop
      clear_stopfile
      log "stopped (with stop file)"
      break
    end

    if latest_submitted_at==nil
      submissions = Submission.all
    else
      submissions = Submission.all(:conditions => ["submitted_at >= :latest", 
                                                   {:latest => latest_submitted_at}])
    end

    graded_any = false

    if submissions.length != 0
      submissions.each do |submission|
        if (submission.problem == nil) or (!submission.problem.available)
          next
        end
        if ! graded_submission_ids[submission.id]
          runner.grade_submission(submission)
          graded_submission_ids[submission.id] = true
          if (!latest_submitted_at or 
              latest_submitted_at < submission.submitted_at)
            latest_submitted_at = submission.submitted_at
          end
          puts "graded: #{submission.id}"
          puts "latest: #{latest_submitted_at}"
          graded_any = true
        end
      end
    end

    if ! graded_any
      sleep(1)
    end
  end 
end

def grader_grade_problems(grader_proc, options)
  if options[:report]
    result_collector = ResultCollector.new
  else
    result_collector = nil
  end

  if options[:dry_run]
    puts "Running in dry mode"
  end

  prob_reporter = Grader::SubmissionReporter.new(:dry_run => options[:dry_run],
                                                 :result_collector => result_collector)
  engine = Grader::Engine.new(:reporter => prob_reporter)
  runner = Grader::Runner.new(engine, grader_proc)
  
  grader_proc.report_active if grader_proc!=nil
  
  ARGV.each do |prob_name|
    prob = Problem.find_by_name(prob_name)
    if prob==nil
      puts "cannot find problem: #{prob_name}"
    else
      runner.grade_problem(prob,options)
    end
  end

  if options[:report]
    result_collector.print_report_by_user
  end
end

def grader_grade_contests(grader_proc, options)
  # always use dry run when grading during contest
  dry_run = options[:dry_run] = true

  contest_name = ARGV.shift

  contest = Contest.find_by_name(contest_name)
  if contest==nil
    puts "cannot find contest: #{contest_name}"
    exit(0)
  end
  
  if options[:report]
    result_collector = ResultCollector.new
  else
    result_collector = nil
  end

  if options[:dry_run]
    puts "Running in dry mode"
  end

  prob_reporter = Grader::SubmissionReporter.new(:dry_run => dry_run,
                                                 :result_collector => result_collector)
  engine = Grader::Engine.new(:reporter => prob_reporter)
  runner = Grader::Runner.new(engine, grader_proc)
  
  grader_proc.report_active if grader_proc!=nil
  
  contest.problems.each do |problem|
    puts "Grading: #{problem.name}"
    runner.grade_problem(problem, 
                         :user_conditions => lambda do |u| 
                           u.contest_finished? and 
                             u.contest_ids.include?(contest.id)
                         end)
  end
  
  if options[:report]
    result_collector.print_report_by_user
  end  
end

def grader_grade_submissions(grader_proc, options)
  engine = Grader::Engine.new
  runner = Grader::Runner.new(engine, grader_proc)

  grader_proc.report_active if grader_proc!=nil

  ARGV.each do |sub_id|
    puts "Grading #{sub_id}"
    begin
      submission = Submission.find(sub_id.to_i)
    rescue ActiveRecord::RecordNotFound
      puts "Submission #{sub_id} not found"
      submission = nil
    end

    if submission!=nil
      runner.grade_submission(submission)
    end
  end
end

#########################################
# main program
#########################################

options = process_options_and_stop_file
GRADER_ENV = options[:environment]
grader_mode = options[:mode]
dry_run = options[:dry_run]

puts "environment: #{GRADER_ENV}"
puts "grader mode: #{grader_mode}"
require File.join(File.dirname(__FILE__),'config/environment')

# add grader_mode to config
# this is needed because method log needs it.  TODO: clean this up
class << config
  attr_accessor :grader_mode
end
config.grader_mode = grader_mode

# reading rails environment
log 'Reading rails environment'

RAILS_ENV = config.rails_env
require RAILS_ROOT + '/config/environment'

# register grader process
if config.report_grader
  grader_proc = GraderProcess.register(config.grader_hostname,
                                       Process.pid,
                                       grader_mode)
else
  grader_proc = nil
end

#set loggin environment
ENV['GRADER_LOGGING'] = log_file_name
if options[:err_log]
  err_file_name = log_file_name + '.err'
  $stderr.reopen(err_file_name,"a")
  log "STDERR log to file [#{err_file_name}]"
  warn "start logging for grader PID #{Process.pid} on #{Time.now.in_time_zone}"
end


# register exit handler to report inactive, and terminated
at_exit do
  if grader_proc!=nil
    grader_proc.report_inactive 
    grader_proc.terminate
  end
end

#
# MAIN LOOP
#

case grader_mode
when "queue"
  grader_queue_loop(grader_proc, options)

when "test_request"
  grader_test_request_loop(grader_proc, options)

when "prob"
  grader_grade_problems(grader_proc, options)

when "contest"
  grader_grade_contests(grader_proc, options)

when "sub"
  grader_grade_submissions(grader_proc, options)

when "autonew"
  grader_autonew_loop(grader_proc, options)

else
  display_manual
  exit(0)
end